1. Field of the Invention
This invention relates to a motor vehicle door lock. More specifically, the present invention relates to a door lock with a control unit separate from a lock unit.
The concept of motor vehicle door lock of this invention should be understood as encompassing not only side door locks and rear door locks, but also, for example, rear hatch locks. The concept of motor vehicle door lock of the present invention means the entire system with components that can also be arranged in a distributed manner.
2. Description of Related Art
Motor vehicle door locks are known in various embodiments. More and more often, motor vehicle door locks can be found with a central interlock drive, opening drive, auxiliary lock drive, driven entirely by electric motor. One example of such a motor vehicle door lock system can be found in published European Patent Application EP 0 894 920 A1, which includes lock elements and lock mechanism having a plurality of micro-switches and proximity sensors, especially Hall sensors, with signals which are evaluated and converted in the lock electronics.
In particular, in the lock mechanism and the lock electronics, the issue of moisture entry is important. The above-mentioned known motor vehicle door lock relates to special shielding measures.
A motor vehicle door or hatch has a damp space facing the outside door wall in which moisture enters from above at the window shaft in an amount that is often considerable, and a dry space that is generally sealed and separated from the damp space and is facing toward the inside of the motor vehicle door or hatch. The lock elements necessarily sit in the damp space as they are normally located on the end face of the motor vehicle door or hatch. In the dry space, there are electrical components such as, for example, a speaker, etc. The damp space/dry space separation has become known in, for example, electrical window raisers.
Also, as shown in published German Patent Application DE 44 44 581 A1, damp space/dry space separation has also been applied in a motor vehicle door lock. In this motor vehicle door lock there are mechanical lock elements, including lock latch and the detent pawl, combined in one lock unit in an encapsulated housing located in a damp space. In a dry space, on the other hand, a lock unit connected via Bowden cables to a separate control unit with an electric drive motor and lock electronics. In the dry space, there is also the inside door handle arrangement. The use of a remote power transmission means, such as the Bowden cable, which penetrates the damp/dry separation of the motor vehicle door or hatch, makes it possible to house the moisture-sensitive control unit in the dry space without adversely affecting the serviceability of the motor vehicle door lock overall.
In the above-discussed published prior art, not less than five mechanical connections by the remote power transmission means and an undisclosed number of electrical connection elements are necessary, especially for interrogation and supply of sensors for scanning the position of the lock latch or the like. Accordingly, the associated cost is considerable with such door lock systems which prevents practical introduction of these motor vehicle door locks.
It is therefore an object of the invention is to optimize the above explained known concept of damp space/dry space separation for a motor vehicle door lock.
In an embodiment of the invention, the information of the locked position or the main catch position of the lock latch is transmitted mechanically via the remote power transmission means to the control unit. In this embodiment, the motion of the lock latch into the closed position or the main catch position exerts an actuating force on the remote power transmission means, and the motion of the remote power transmission means resulting therefrom can be evaluated by circuitry in the control unit. In doing so, the lock element, especially the detent pawl, is actuated by means of a drawing function of the remote power transmission means in the first direction. By means of the drawing function of the remote power transmission means in a second direction opposite the first direction, reaching the locked position or the main catch position of the lock latch is mechanically signaled.
This results in the desired scanning of the position of the lock latch that can be routed to the control unit by an existing connecting element, specifically the remote power transmission means. An electrical connecting element between the lock unit and the control unit can be abandoned in this regard.
In another embodiment, the remote power transmission means is coupled to the lock element, i.e., the detent pawl, with an inclusion of a bilateral freewheel. This arrangement allows the lock latch a certain overstroke with the detent pawl already engaged and optionally allows trailing engagement for the detent pawl when the motor vehicle door lock is closed.
To be able to recognize reaching of the locked position or the main catch position of the lock latch by the motion of the remote power transmission means in the control unit as reliably as possible, it is desirable for the motion of the remote power transmission means which is to be detected to be much greater than all inaccuracies caused by tolerances, etc. Generally, this motion will also be much greater than the possible deflection of the detent pawl so that a correspondingly large freewheel must be provided.
A large freewheel means that, when the lock latch is in the locked position or in the main catch position for raising the detent pawl, fundamentally the existing freewheel must be xe2x80x9cbridged.xe2x80x9d This is especially a problem in that the actuating forces on the outside door handle and on the inside door handle should be as small as possible in order to achieve maximum ease of use. These small actuating forces can generally be implemented by corresponding multiplication so that a low activation force is xe2x80x9cboughtxe2x80x9d at the cost of a large actuating stroke. It is obvious that the aforementioned freewheel is problematical.
In yet another embodiment, a large movement of the remote power transmission means can be accomplished compared to the lifting motion of the detent pawl without having to tolerate a freewheel. When the lock latch is in the locked position or the main catch position the actuating force on the remote power transmission means directly causes an actuating force on the detent pawl. The freewheel is largely avoided by an adjustable intermediate element which is dynamically coupled to the lock latch.